While that figure may only represent 6% of the global web
population, ad blocking is expected to cost publishers more than
$21.8 billion in 2015 in lost revenue. That represents 14% of
global ad spend. By 2016, PageFair and Adobe predict the global
cost of ad blocking to rise to $41.4 billion.

This chart, which chronicles ad blocking growth from 2009 shows
how ad blocker use really started to accelerate
from 2013. And while the 41% increase this year was down on
the near 70% growth PageFair and
Adobe reported between 2013 and 2014, it's nevertheless a
worrying trend for publishers.

Dr Johnny Ryan, PageFair's head of ecosystem, told Business
Insider: "Ad blocking has grown virally along a classic s-curve
to 50+ million ad blocking users at the end of 2012, and onward
to 198 million at the end of Q2 2015. This viral growth, and the
climb up the curve you describe, is explained by our findings in
last
year's 2014 report (page nine) that the majority of ad block
users find out about ad blocking by word of mouth and through
their own online research. Ad blocking is a viral phenomenon that
will continue."

The rate of ad blocking varies country by country. The US has an
estimated 45 million monthly active ad block users, up 48%
year-on-year.

Across Europe, 35% of the internet population (77 million users)
used an ad blocker at least once a month. Greece has the highest
rate of ad block usage in Europe, with 36.7% of internet users in
the country using ad block software.

As per previous research in this area, PageFair and Adobe found
that ad block users are typically, young, technically savvy, and
more likely to be male.

Here are the types of websites affected most by ad
blocking.

PageFair
and Adobe

Right now, ad blocking almost always happens via desktop
computers, even though 38% of web browsing happens on mobile.
Just 1.6% of ad block traffic on the PageFair network was from
mobile devices.

PageFair and Adobe say this could be a "game changer." Apple's
Safari mobile browser represents 52% of mobile browsing and 14%
of total web browsing. By making it easier to download ad
blocking software, ad block usage could soar when iOS9
becomes available in the fall.
However, as ad tech company Criteo's president and COO Eric
Eichmann pointed out last week, users will still need to
manually download the "obscure" software themselves, meaning the
iOS9 update might not be as big and immediate a catalyst as
feared.

PageFair
and Adobe

As part of their report, PageFair and Adobe surveyed 400
people in the US about the reasons they might start or have
started using ad blockers. Of those who are currently not using
ad blocking extensions, the misuse of personal information by
advertisers and publishers was the primary reason that would
convince them to change their mind.

But PageFair's Ryan said performance is not as much of a key
motivator as some people might think. Just 8% of respondents in
PageFair and Adobe's report last year cited performance as their
main reason for installing an ad blocker.

PageFair has been tracking the growth of ad blocking for three
years, and measures more than a billion ad blocking hits each
month across its 3,000+ clients' websites. The company provides
publishers with analytics to measure how many of their visitors
are blocking ads and a system that displays "adblock-friendly"
ads to ad block users.ad